As a leading historian of Native Americans, Alvin Josephy, who has died aged 90, wrote, co-wrote or edited a score of books on them. But his first - after publishing two works on his wartime experiences - did not appear until his mid-40s, an indication of the subject's humble position in US publishing.

It was not that Josephy did not try. He worked for Henry Luce's Time magazine in the early 1950s and agitated for a large feature on American Indians, in whom he had become interested after a trip to the west. But Luce, Josephy later wrote, referred to Indians perversely as "phonies", because "they refused to give up their reservation and live like everyone else".

The Patriot Chiefs, his first book on Native Americans, published in 1961, was the story, as its subtitle suggested, of their resistance to white American dominance and oppression. Among his other works the more important were: The Nez Perce Indians and the Opening of the Northwest (1965), The Indian Heritage of America (1968), Red Power (1971), Now That the Buffalo's Gone (1982) and The Civil War in the American West (1991). For such works as these, a New York Times critic called him the "leading non-Indian writer about Native Americans".

As a boy he had been fascinated by a story that there was once an Oregon property in the family, and he always wanted to visit the state. He not only did so, conducting much of his first-person research there and in neighbouring states, but eventually bought a home in Joseph, beneath Oregon's Wallowa mountains. Josephy (pronounced Jos-EFF-y), whose middle initial M always appeared on his books but stood for nothing, called his 2000 memoir A Walk toward Oregon.

The town of Joseph was named after a Nez Perce chief and Moses tribal figure of the 1870s, when American miners swarmed on to their lands and the US army forced them into a much smaller Idaho reservation. Some tribesmen rebelled and fled 1,700 miles towards Canada and freedom, but were defeated at a battle in Montana in 1877.

The story had caught Josephy's imagination early on. Despite this love of the wild west, Josephy was born into a well-connected Long Island family and raised in New York. He was related on his mother's side to the Knopf publishing family, and the great journalist and curmudgeon HL Mencken was a visitor.

Josephy wanted to be a writer but had to leave Harvard because of the Depression. He drove across America to Hollywood and the MGM studios, where he became a junior screenwriter for short musicals "about dancing bras and panties," he recalled. Then came a miserable Wall Street brokerage job. Life improved with journalism in Mexico, where he interviewed the exiled Russian revolutionary, Leon Trotsky.

During the second world war he followed US marines as a combat correspondent in the Pacific and won a medal. With peace, he returned to Hollywood and also investigated gangsters for a local newspaper. This he turned into a screenplay for the 1952 film, The Captive City, directed by Robert Wise and starring John Forsythe as a crusading reporter.

Its success led to his Time job, where he began research on American Indians. But in the libraries he found existing works "shelved in the natural history section along with books about snails and dinosaurs, that sort of thing".

His Indian books stimulated official interest, and he became a consultant on federal Native American policy, even writing a study for President Richard Nixon. In the 1990s, Josephy helped to found the National Museum of the American Indian, which opened in Washington last year.

His first marriage ended in divorce, and his second wife of 56 years died last year. Three daughters and a son survive him.